arm64: Call swiotlb_init() instead of swiotlb_init_with_default_size()

Following commit 74838b7 (swiotlb: add the late swiotlb initialization
function with iotlb memory) the swiotlb_init_with_default_size() is a
static function. This patch changes the arm64 code to call
swiotlb_init() instead and use the default size of 64MB. It is assumed
that AArch64 platforms have enough RAM to afford the pre-allocated
swiotlb memory. It also removes the #ifdef around this call since
CONFIG_SWIOTLB is always enabled.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/mm/mm.h b/arch/arm64/mm/mm.h
index d8d6e78..916701e 100644
--- a/arch/arm64/mm/mm.h
+++ b/arch/arm64/mm/mm.h
@@ -1,2 +1,3 @@
 extern void __flush_dcache_page(struct page *page);
 extern void __init bootmem_init(void);
+extern void __init arm64_swiotlb_init(void);